Think of this as blowback. President Obama's campaign has intensified the questioning of Mitt Romney's business record.

MONTAGNE: That is what candidates often do - work to define the opponent. Republicans are pushing back, defending Romney's record at a private equity firm and attacking the attack.

INSKEEP: This political debate inevitably came up when the president took questions at a meeting of world leaders that was supposed to be focused on the war in Afghanistan.

NPR's Scott Horsley reports from Chicago.

SCOTT HORSLEY, BYLINE: Even at a NATO summit meeting, domestic politics is never far from the surface. At a post-summit news conference, Mr. Obama was asked about the tough attacks his campaign has been waging against Mitt Romney's business record. Some of the president's own allies have criticized those attacks as going too far. But Mr. Obama says he's not backing down.

PRESIDENT BARACK OBAMA: This issue is not a, quote, "distraction." This is part of the debate that we're going to be having in this election campaign about how do we create an economy where everybody - from top to bottom, folks on Wall Street and folks on Main Street - have a shot at success.

HORSLEY: The Obama campaign suggests that Romney's success came at least in part at the expense of ordinary workers, some of whom lost out when companies that Romney's firm invested in slashed wages, cut jobs, and in some cases went bankrupt.

Mr. Obama says it's fair game to spotlight those workers, since Romney's citing his business background as his principal qualification for the White House.

OBAMA: If your main argument for how to grow the economy is I knew how to make a lot of money for investors, then you're missing what this job is about.

HORSLEY: Mr. Obama says a president's job is not simply to maximize profit in the short-term, but to build lasting economic opportunity for everyone.

With the economy at the center of the election, Mr. Obama's chances for a second term could be threatened by the European debt crisis. The president says he sensed a greater urgency about addressing those problems when he met with G-8 leaders over the weekend.

At the NATO meeting in Chicago, the main focus was Afghanistan and a new milestone that calls for Afghan security forces to take the lead in all combat operations by next summer. NATO Secretary General Anders Fogh Rasmussen says that should be welcomed in the country after more than a decade of war.

ANDERS FOGH RASMUSSEN: The people of Afghanistan increasingly see their own army and police in their towns and villages, providing their security.

HORSLEY: Pakistan's President Asif Ali Zardari also attended the NATO summit, where he spoke briefly with Mr. Obama. The U.S. and Pakistan remain uneasy allies after the U.S. raid that killed Osama bin Laden and the accidental killing of 24 Pakistani troops last November.

OBAMA: I don't want to paper over real challenges there.

HORSLEY: Mr. Obama called the tensions inevitable after a long war, and said Pakistan's president told him he thinks they can be worked through.

OBAMA: It is in our interest to see a successful, stable Pakistan. And it is in Pakistan's interests to work with us and the world community to ensure that they themselves are not consumed by extremism that is in their midst.

HORSLEY: Pakistan has not yet agreed to re-open supply routes to Afghanistan that were closed in the wake of the November troop deaths. NATO's secretary-general says he expects those routes will reopen shortly. But in a telling sign, he spoke about using the routes to move international troops and supplies out of Afghanistan rather than in.